Compositions for displacing water adhering to metal surfaces and process

ABSTRACT

A composition for the displacing of an aqueous film or layer adhering to a metal surface consisting essentially of an organic water-immiscible solvent selected from the group consisting of an organic water-immiscible solvent having a density of less than 0.9 gm./ml. and a mixture of miscible organic water-immiscible solvents, said mixture having a density of less than 0.9 gm./ml., containing from 0.1 to 10 percent of an acid selected from the group consisting of monocarboxylic acid having from seven to 12 carbon atoms and mixtures of monocarboxylic acids having an average of from seven to 12 carbon atoms and from 0.1 to 8 percent of an alkylamine selected from the group consisting of alkylamines having from six to 10 carbon atoms and mixtures of alkylamines having an average of from six to 10 carbon atoms, the average sum of the carbon atoms in said acid and said alkylamine being from 15 to 17; as well as the process of removing adhering liquid utilizing said composition.

States t Ziehr et a1. 5] Apr. 4, 1972 s41 COMPOSITIONS FOR DISPLACING3,397,150 8/1968 Burt et al. ..252/194 WATER ADHERING TO METAL 3,466,2079/1969 Vincent et a1. ..l48/6.2 SURFACES AND PROCESS FOREIGN PATENTS ORAPPLICATIONS 1721 Invent (1W8 Dusseldorf-flolthausen; 623,004 3/1963Belgium 148/614 Heinz-Dieter I-Ieidenbluth, Dusseldorf, both of GermanyPrimary ExaminerRalph S. Kendall [73] Assignee: Henkel & Cie GmbH,Dusseldorf- Att0'"ey Hammnd Lute H 1th G o ausen ermany ABSTRACT 22 F1d: N 13 1969 1 l C 0v A composition for the displacing of an aqueousfilm or layer [21] App]. No.: 876,604 adhering to a metal surfaceconsisting essentially of an organic water-immiscible solvent selectedfrom the group consisting of an organic water-immiscible solvent havinga density of less [30] Foreign Apphcauon Prlomy Data than 0.9 gm./ml.and a mixture of miscible organic water-im- Nov. 22, 1968 Germany ..P 1810 245.9 miscible solvents, said mixture having a density of less thangm./m1., containing from 0.1 to 10 percent of an acid selected 52 us.c1. ..l48/6.14 R, 34 9, 252 194, from the group consisting ofmonocarboxylic acid having from 5 392 seven to 12 carbon atoms andmixtures of monocarboxylic [51] Int. Cl ..B01d 12/00 acids having anaverage of from seven to 12 carbon atoms and [58] Field of Search..148/6.14, 615- 34/9- 252 194 from 8 Percent of alkylamine selwed the2527392 group consisting of alkylamines having from six to 10 carbonatoms and mixtures of alkylamines having an average of from 56 R f d sixto 10 carbon atoms, the average sum of the carbon atoms 1 e erences l ein said acid and said alkylamine being from 15 to 17; as well as UNITEDSTATES PATENTS the process of removing adhering liquid utilizing saidcomposition. 2,250,508 7/1941 Thompson et al. ..148/6.14 3,003,24710/1961 Sherliker ..34/9 8 Claims, N0 Drawings COMPOSITIONS FORDISPLACING WATER ADHERING TO METAL SURFACES AND PROCESS THE PRIOR ART Inthe surface treatment of metal articles with aqueous solutions it isusually necessary to remove adhering aqueous liquid films or layers fromthe metal surfaces. After rinsing with water, the parts are generallydried with warm air. When the water is evaporated, small drops areformed which may lead to spots or stains. Frequency the last traces ofliquid are only difficulty removed, even by use of compressed air, fromblind holes and bore holes in the metal objects. Attempts have also beenmade to use absorbents for drying moist objects. This method iseffective, but is time-consuming and generally unsuitable, for example,for the treatment of objects containing drill holes.

A special method is drying with use of organic solvents. In such casethe water may be removed azeotropically by means of solvent vapors. Inthe immersion process, it is also known to displace the water by organicsolvents when certain surfaceactive compounds such as, for example,quaternary ammonium compounds, fatty acid polyglycol esters or similarcompounds are added to these solvents. However, it has been found inthis known method the displaced water easily becomes emulsified and thenresidues remain on the surface.

OBJECTS OF THE INVENTION An object of the present invention is thedevelopment of a composition and a process for removing adhering aqueousfilms or layers from metal surfaces while avoiding the drawbacks of theprior art.

Another object of the invention is the obtaining of a composition forthe displacing of an aqueous film or layer adhering to a metal surfaceconsisting essentially of an organic waterimmiscible solvent selectedfrom the group consisting of an organic water-immiscible solvent havinga density of less than 0.9 gm./ml. and a mixture of miscible organicwater-immiscible solvents, said mixture having a density of less than0.9 gm./ml., containing from 0.1 to 10 percent of an acid selected fromthe group consisting of monocarboxylic acid having from seven to 12carbon atoms and mixtures of monocarboxylic acids having an average offrom seven to 12 carbon atoms and from 0.1 to 8 percent of an alkylamineselected from the group consisting of alkylamines having from six to 10carbon atoms and mixtures of alkylamines having an average of from 6 to10 carbon atoms, the average sum of the carbon atoms in said acid andsaid alkylamine being from l to I7.

A yet further object of the invention is, in the process of removing anadhering aqueous film or layer from a metal surface by the steps ofdisplacing said adhering aqueous film or layer on a metal surface withan organic solvent composition and removing said organic solvent fromsaid metal surface the improvement which comprises utilizing, as saidorganic solvent composition, a composition for the displacing of anaqueous film or layer adhering to a metal surface consisting essentiallyof an organic water-immiscible solvent having a density of less than 0.9gm./ml. and a mixture of miscible organic water-immiscible solvents,said mixture having a density of less than 0.9 gm./ml., containing from0.1 to percent of an acid selected from the group consisting ofmonocarboxylic acid having from seven to 12 carbon atoms and mixtures ofmonocarboxylic acids having an average of from seven to 12 carbon atomsand from 0.1 to 8 percent of an alkylamine selected from the groupconsisting of alkylamines having from six to 10 carbon atoms andmixtures of alkylamines having an average of from six to 10 carbonatoms, the average sum of the carbon atoms in said acid and saidalkylamine being from 15 to 17.

These and other objects of the invention will become more apparent asthe description thereof proceeds.

DESCRIPTION OF THE INVENTION In one aspect, therefore, the presentinvention provides a composition, for the removal of aqueous liquidfilms or layers from a metal surface comprising a water-immiscibleorganic solvent, or mixture of such solvents having a density or anaverage density of less than 0.9 gm./ml., containing from 0.1 to 10percent by weight of a monocarboxylic acid or a mixture ofmonocarboxylic acids, having an average of from seven to 12 carbon atomsand 0.1 to 8 percent by weight of an alkylamine having six to 10 carbonatoms, or a mixture thereof having an average of from six to 10 carbonsatoms, the sum of carbon atoms in the carboxylic acid and the alkylaminebeing 15 to 17.

In a further aspect, the present invention provides a process for theremoval of an aqueous liquid film or layer adhering to a metal surfacecomprising treating said metal surface with a water-immiscible organicsolvent or a mixture of such solvents having a density or an averagedensity of less than 0.9 gm./ml., containing from 0.1 to 10 by weight ofa monocarboxylic acid, or a monocarboxylic acid mixture having anaverage of from seven to 12 carbon atoms, and 0.1 to 8 percent of analkylamine with six to 10 carbon atoms, or a mixture thereof having anaverage of from six to 10 carbon atoms, the sum of carbon atoms in thecarboxylic acid and alkylamine being l5 to 17, in order to displace saidaqueous liquid film or layer from the surface of said metal surface.

Hydrocarbon fractions with a density of less than 0.9 gm./ml. aregenerally suitable as the organic solvent mixtures immiscible withwater. If desired, small amounts of chlorinated hydrocarbons may beadded as long as they are water-immiscible and miscible with thehydrocarbon fractions and the average density of the mixture is lessthan 0.9 gm./ml.

It is generally advantageous to keep the density of the solvent as lowas possible in order to bring about a rapid separation of the displacedwater. Hydrocarbons with boiling ranges between and 250 C. or fractionsfrom this boiling range are generally used. Apart from this, organicsolvents of the said type possess a relatively low flammability and,after the metal articles are removed from the treatment bath, ensure arapid evaporation of the solvent.

The carboxylic acids used may be straight or branched chains, natural orsynthetic monocarboxylic acids or their mixtures, having an average offrom seven to 12 carbon atoms in the molecule. For example, alkanoicacids having from seven to 12 carbon atoms, such as oenanthic acid,caprylic acid, pelargonic acid, capric acid, lauric acid or the branchedacids corresponding to these carboxylic acids may be used. In additionto these aliphatic carboxylic acids, aromatic carbox ylic acids, such asphenylalkanoic acids and alkylphenylalkanoic acids having from seven to12 carbon atoms, especially benzoic acids, may also be used. Thecarboxylic acid used can preferably be a readily accessible, commercialfatty acid mixture which contains a preponderance of caprylic, capricand lauric acids. Such mixtures are obtained, for example, as the firstdistillate during the working up of natural fats and usually consist ofabout 50 percent of caprylic acid, 40 percent of capric acid and 5percent of lauric acid, as well as small amounts of lower carboxylicacids. This mixture of alkanoic acids from the first distillate has anaverage of nine carbon atoms.

Suitable alkylamines having six to 10 carbon atoms are preferablyprimary amines such as hexylamine, octylamine and decylamine, ormixtures thereof. The monocarboxylic acids or mixtures of monocarboxylicacids and the alkylamines or their mixtures are preferably used inapproximatly equimolecular amounts. Small excesses of carboxylic acid oralkylamine, however, have no effect on the activity.

Compositions are preferably used which contain from 0.3 to 3 percent byweight each of carboxylic acid and alkylamine. Basically compositionswith a content of carboxylic acid and alkylamine each of less than 0.3percent can be also make, but their stability is too low for a technicalproduct. With higher concentrations of carboxylic acid and aklylamine,alkylamine, a slight film remains on the metal surfaces which, however,exerts a positive influence on their storability.

It is essential that the total number of carbon atoms in the carboxylicacid and alkylamine should be to 17. In the case of mixtures thecalculated average number of carbon atoms is decisive as the carbonnumber of the carboxylic acid and the alkylamine. If the carbon numberis too small, multilayer liquid systems are formed on the introductionof water. The efficiency of the water displacement is too low. If, onthe other hand, the total carbon atoms number is too high, emulsions areformed with the displaced water.

In order to remove the aqueous liquid layers, the wet metal surfaces arepreferably introduced for a short time into a bath which contains theabove-indicated components. In general, a treatment period of a fewseconds is sufficient to free the metal surfaces from the adherent filmof water. The displaced water is easily separated. No formation ofemulsions occurs, so that the water can be easily removed. The metalparts are then taken out of the bath. After evaporating the solvent,hydrophobic surfaces from the residual acid and amine remain which givea temporary protection against corrosion. If it is desired to store themetal objects for a long period, a customary fat for protection againstcorrosion, such as for example wool fat or vaselines, can beincorporated in the compositions according to the invention.

The following specific embodiments are illustrative of the practice ofthe invention without being deemed limitative in any respect.

The percentage figures given in the following Examples are percentagesby weight, unless the contrary is indicated.

EXAMPLE I la. Dirty metal articles, which were first treated with analkaline cleaning solution and were then thoroughly rinsed with water,were immersed in the wet state in a bath of the follow' ing composition1.2 percent of first distillate of a fatty acid mixture from the workingup of natural fats (calculated carbon number 9) and 1.0 percent ofoctylamine, dissolved in a mixture of 93.8 percent of hydrocarbonfraction with a boiling range at 760 mm. Hg of 180 to 210 and 4.0percent of perchlorethylene (Average sum of the carbon atoms in the acidand amine =17).

The water adhering to the surface was immediately displaced without theinformation of an emulsion or a multiphase in the bath. On taking theparts from the solvent the small amount of solvent evaporated, and dryhydrophobic metal surfaces were obtained.

Ib. For comparison, the metal objects were treated, with otherwise thesame method, with a solution in the immersion process which contained 2percent caprylic acid 1.5 percent hexylamine 96.5 percent of ahydrocarbon with a boiling range at 760 mm. Hg of 180 to 210C,

The total carbon number of the composition was therefore 14.

A displacement of water from metal surfaces indeed also occurred, butafter incorporating a small amount of water, the composition separatedinto three layers.

Ic. In a further comparative experiment, the metal objects were finallyimmersed in a solution which contained:

2 percent lauric acid 1 percent hexylamine 97 percent of a hydrocarbonwith a boiling range at 760 mm. Hg of 180 to 210 C. with otherwise thesame method of operation. The total carbon number of the composition wastherefore 18.

A displacement of the film of water likewise occurred, but the waterremoved formed an emulsion at the interface with the organic phase,particularly when movement of the bath occurred when the parts were putin and taken out.

EXAMPLE 2 Oiled metal sheets contaminated with a machine oil weretreated with an acid cleaner and then rinsed with water. The sheets werethen dipped in a bath of the following compositlons:

2.2 percent of a mixture of caprylic acid and lauric acid (proportion 2:1)

1.5 percent hexylamine 96.3 percent of an aliphatic hydrocarbon mixturewith a boiling range at 760 mm. Hg of 155 to 195. (Average sum of thecarbon atoms in the acid and amine =15 1 3 After taking the sheets outof the bath and evaporating the solvent, clean dry surfaces wereobtained.

EXAMPLE 3 Slightly soiled metal parts were treated with a neutralcleaner and then rinsed with water. The metal parts were then immersedin a bath of the following composition:

5.6 percent caprylic acid and 5.0 percent octylamine, dissolved in 89.4percent of an aliphatic hydrocarbon mixture with a boiling range at 760mm. Hg of 155 to 210 C.

After a few seconds the water adhering to the surface was displaced, andafter the removal of the metal parts from the bath and evaporation ofthe solvent, a dry hydrophobic metal surface was obtained.

Practically the same results were obtained if, instead of theabove-described bath, a bath of the following composition was used:

1.2 percent benzoic acid and 1.6 percent decylamine, dissolved in 92.2percent of a hydrocarbon with a boiling range at 760 mm. Hgof lto 210C5.0 percent perchlorethylene.

The preceding specific embodiments are illustrative of the practice ofthe invention. It is to be understood, however, that other expedientsknown to those skilled in the art may be utilized without departing fromthe spirit of the invention or the scope of the appended claims.

We claim:

1. A composition for the displacing of an aqueous film or layer adheringto a metal surface consisting essentially of an organic water-immisciblesolvent selected from the group consisting of an organicwater-immiscible solvent having a density of less than 0.9 gm./ml. and amixture of miscible organic water-immiscible solvents, said mixturehaving a density of less than 0.9 gm./ml., containing from 0.1 to 10percent of a monocarboxylic acid having an average of from seven to 12carbon atoms selected from the group consisting of 1 alkanoic acids, 2)phenylalkanoic acids, 3) alkylphenylalkanoic acids 4) mixtures thereofand from 0.1 to 8 percent of an alkylamine selected from the groupconsisting of alkylamines having from six to 10 carbon atoms andmixtures of alkylamines having an average of from six to 10 carbonatoms, the average sum of the carbon atoms in said acid and saidalkylamine being from 15 to 17.

2. The composition of claim 1 wherein said acid and said alkylamine arepresent in substantially equimolecular amounts.

3. The composition of claim 1 wherein said acid is a technical fattyacid mixture consisting preponderantly of caprylic, capric and lauricacids.

4. The composition of claim 1 wherein said acid is benzoic acid.

5. The composition of claim 1 wherein said organic waterimmisciblesolvent is predominately a hydrocarbon fraction.

6. The composition of claim 5 wherein said hydrocarbon fraction has aboiling point range within the range to 250 C.

7. The composition of claim 5 having a further content of a chlorinatedhydrocarbon.

8. In the process of removing an adhering aqueous film or layer from ametal surface by the steps of displacing said adhering aqueous film orlayer on a metal surface with an organic solvent composition andremoving said organic solvent from said metal surface, the improvementwhich comprises utilizing as said organic solvent composition, acomposition consisting essentially of an organic water-immisciblesolvent selected from the group consisting of an organicwater-immiscible solvent having a density of less than 0.9 gm./ml. and amixture of miscible organic water-immiscible solvents, said mixturehaving a density of less than 0.9 gm./ml., containing from 0.1 to 10percent of a monocarboxylic acid having an average of from seven to 12carbon atoms selected from the group consisting of l) alkanoic acids, 2)phenylalkanoic acids, 3) alkylphenylalkanoic acids and 4) mixturesthereof and from 0.1 to 8 percent of an alkylamine selected from thegroup consisting of alkylamines having from six to 10 carbon atoms andmixtures of alkylamines having an average of from six to 10 carbonatoms, the average sum of the carbon atoms in said acid and saidalkylamine being from 15 to l7.

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2. The composition of claim 1 wherein said acid and said alkylamine arepresent in substantially equimolecular amounts.
 3. The composition ofclaim 1 wherein said acid is a technical fatty acid mixture consistingpreponderantly of caprylic, capric and lauric acids.
 4. The compositionof claim 1 wherein said acid is benzoic acid.
 5. The composition ofclaim 1 wherein said organic water-immiscible solvent is predominately ahydrocarbon fraction.
 6. The composition of claim 5 wherein saidhydrocarbon fraction has a boiling point range within the range 150* to250* C.
 7. The composition of claim 5 having a further content of achlorinated hydrocarbon.
 8. In the process of removing an adheringaqueous film or layer from a metal surface by the steps of displacingsaid adhering aqueous film or layer on a metal surface with an organicsolvent composition and removing said organic solvent from said metalsurface, the improvement which comprises utilizing as said organicsolvent composition, a composition consisting essentially of an organicwater-immiscible solvent selected from the group consisting of anorganic water-immiscible solvent having a density of less than 0.9gm./ml. and a mixture of miscible organic water-immiscible solvents,said mixture having a density of less than 0.9 gm./ml., containing from0.1 to 10 percent of a monocarboxylic acid having an average of fromseven to 12 carbon atoms selected from the group consisting of 1)alkanoic acids, 2) phenylalkanoic acids, 3) alkylphenylalkanoic acidsand 4) mixtures thereof and from 0.1 to 8 percent of an alkylamineselected from the group consisting of alkylamines having from six to 10carbon atoms and mixtures of alkylamines having an average of from sixto 10 carbon atoms, the average sum of the carbon atoms in said acid andsaid alkylamine being from 15 to 17.